1. Field of the Invention
The present invention relates generally to communication between an infrared computer keyboard and the associated host computer and in particular to a power saving infrared keyboard transmission method which provides a more effective identification and a more efficient way of data transmission between the infrared keyboard and the host computer.
2. Related Arts
Computers are widely used nowadays to handle a number of jobs, such as word processing communication, and business transactions. In using a computer, a man-machine interface, such as input device, is of vital importance. One of the most commonly known input device is the keyboard and thus the efficiency and effectiveness in operating the keyboard plays an important role in user-controlling the computer.
Conventionally, the keyboard is coupled to the computer by means of a cable which transmits data/information between the keyboard and the host computer. However, with such a physical connection between the keyboard and the computer, it may be somehow difficult for a computer user to readily move the keyboard as he or she wishes. To overcome such a problem, cordless keyboards, such as infrared keyboards, are also available in the market wherein the keyboard is coupled to the computer in a cordless manner, such as by means of infrared signal transmitted between the keyboard and the host computer. The most important factors that control the performance of the infrared keyboard is the precision and efficiency of data/signal receiving and transmission which affects the sensitivity of the infrared keyboard.
Conventionally, the infrared keyboard encodes and transmits the information to be transmitted by means of a transmission modulus in the form of an infrared signal comprised of a series of pulses and a receiving modulus is used to receive and decode the signal. To avoid unnecessary interference from other infrared transmitters and to correctly receive the signal, the period of each of the pulses of the infrared signal has to be increased. This elongates the time interval when the infrared transmitter is maintained active in the "ON" condition which consumes power and lowers down the efficiency of data receiving operation.
Furthermore, in such a conventional way of data transmission, there may be likelihood of data missing or signal discontinutiation/interruption, for example, when the depression of a key is not firm which causes an unrecognisable signal. In such a case, the receiving modulus is not capable to correctly decode (interpret) the signal received so that repeatedly depressing the same key is required, which lowers down the sensitivity and correctness of the keyboard operation. This causes an unnecessary waste of time and power.
It is thus desirable to have a method for efficiently and effectively transmitting data between an infrared keyboard and a host computer so as to overcome the problems encountered in the prior art.